In general, workpieces or substrates can be processed or treated, for example worked, coated, heated, etched and/or structurally modified. One method for coating a substrate is that of cathode sputtering, known as sputtering or sputter deposition. For sputtering, a plasma-forming gas (known as the working gas) can be ionized by means of a cathode and the plasma thereby formed used for atomizing material to be deposited, known as the target material. The atomized target material can then be brought to a substrate, on which it can be adsorbed and form a layer.
A modification of cathode sputtering is for example sputtering by means of a magnetron, known as magnetron sputtering. For magnetron sputtering, the forming of the plasma may be supported by means of a magnetic field, which can influence the rate of ionization of the plasma-forming gas. This may involve the formation of an intensive plasma in the form of a channel of plasma, which follows the distribution of the magnetic field. A uniform removal of target material may require that it is moved in relation to the channel of plasma, and consequently in relation to the magnetic field. For this purpose, the cathode may be of a tubular design, known as a tubular cathode, which may have a basic target tube (also known as the carrier tube), the outer lateral surface of which is at least partially covered with target material. A magnet system for generating the magnetic field may be arranged inside the basic target tube, so that when the basic target tube is rotated about the magnet system the target material arranged on the basic target tube moves under the channel of plasma and can thereby be removed and atomized layer by layer.